1. Technical Field
The present invention relates to a liquid ejecting head for providing a pressure change to a pressure chamber communicating with a nozzle and ejecting a liquid in a pressure chamber from the nozzle, a liquid ejecting apparatus, and a method for manufacturing the liquid ejecting head.
2. Related Art
A liquid ejecting head for ejecting liquid droplets from a nozzle by providing a pressure change to a liquid in a pressure chamber may be, for example, an ink jet recording head (hereinafter, simply referred to as a recording head) used for an image recording device such as an ink jet recording device (hereinafter, simply referred to as a printer), a colorant ejecting head used for manufacturing a color filter of a liquid crystal display or the like, an electrode material ejecting head used for forming an electrode of an organic EL (Electro Luminescence) display, a FED (Field Emission Display) or the like, a bio-organism ejecting head used for manufacturing a biochip (a biochemical element) or the like.
For example, the above recording head may be configured so that a channel unit having a series of liquid channels formed from a reservoir to a nozzle via a pressure chamber, an oscillator unit having a piezoelectric oscillator capable of changing a capacity of the pressure chamber or the like is attached to a head case made of resin material. In the recording head, a head case having a runout concave portion and an atmosphere opening path for opening the runout concave portion to the atmosphere, which are formed at a portion opposite to a compliance unit formed by partitioning a part of the reservoir, is known (for example, JP-A-2003-53968). The compliance unit is formed in a state where an opening surface of the reservoir is sealed with an elastic film so that the pressure change of the ink in the reservoir is absorbed by elastic deformation. The runout concave portion is a vacant portion with a size not disturbing the deformation of the compliance unit. In a state where the corresponding runout concave portion is hermetically sealed, there is no place for the air in the runout concave portion to leak, and so normal operation of the compliance unit is difficult. For this reason, the runout concave portion is opened to the atmosphere through the atmosphere opening path.
However, in the recording head as above, since a plurality of runout concave portions are formed corresponding to a plurality of compliance units, a plurality of atmosphere opening paths respectively communicating with each runout concave portion are formed through the head case, thereby weakening the strength of the head case. As a result, for example, when the piezoelectric oscillator is oscillated to eject an ink from the nozzle, the corresponding oscillation may be easily transferred through the head case to another piezoelectric oscillator, and this oscillation may exert an influence on the drive of the corresponding another piezoelectric oscillator. Therefore, the liquid ejection characteristics (the amount of liquid ejected from the nozzle, or flying speed of the liquid ejected from the nozzle) may vary (a so-called crosstalk problem) between the case where a single piezoelectric oscillator is driven independently and the case where a plurality of piezoelectric oscillators are driven simultaneously.